As a retired Mechanical Engineer and auto/truck mechanic before that, I know way too much about Chemistry, Thermodynamics and the internal combustion engine and the combustion process to even begin to support the addition of alcohol to gasoline. The original premiss of putting alcohol into gasoline was to introduce additional oxygen into the combustion which the uninformed said would reduce emissions. While there may have been a crystal of a good idea back in the 1970's and in older cars, the technology of the automobile has cancelled that out completely when the fixed air-to-fuel ratio of a carburetor was replaced by electronic fuel injection with oxygen sensors in the exhaust which fed exhaust oxygen content to the engine control computer which adjusts the air-to-fuel automatically. The extra oxygen introduced by the alcohol is merely read by the exhaust sensor as the engine is running lean and so enriches the air-to-fuel ratio right back to where it would have been to produce the range of oxygen in the exhaust desired (slightly extra oxygen to ensure complete combustion but no more). The whole feedback loop causes more alcohol enriched gasoline to be burned than if it were gasoline alone. This is why the alcohol in gasoline hurts gas mileage. It's a thermodynamic and chemical inescapable fact. All one needs to do to confirm the disasterous effect of alcohol on fuel mileage is run a few tankfuls of gasoline without alcohol through their car and monitor the mileage with and without alcohol. The loss of mileage is profound - I've measured as much as 25% loss of mileage in my vehicle. Since the alcohol addition is only 10%, I'd use less gasoline if I used pure gasoline. In other words, the alcohol actually INCREASES the consumption of the pure gasoline in the nation's cars.
Then, we need to add the expense of the more exotic metals and elastomers that the use of oxygenated fuel requires in the construction of the car. Older cars and other internal combustion engines that weren't designed for alcohol in the fuel can be and are damaged by the alcohol. I have two engines in this category of my own - a chainsaw and an emergency generator - both damaged by the alcohol in the fuel. Long term use results in valve and valve seat damage. I have an old farm truck that I just had to have over $400 worth of machine work done to the cylinder heads to install hardened valve seats to replace the ones ruined by the alcohol laced gasoline.
Evaporative emissions also seem to be worse for alcohol laced gasoline than for gasoline alone - all one has to do is catch a whiff of alcohol laced fuel to know that.
Finally, the massive economic impact that diverting so much farm output to the production of alcohol is anyone's guess. I know turkey and beef farmers who have been put out of business by the higher costs of feed. Corn and grain diverted to make alcohol makes the cost of the food on my table and your be higher, so we're paying for this disaster about 4 different ways. The whole thing needs to be thrown on the rubbish heap of erroneous ideas.
If the ethanol levels mandated by the Renewable Fuel Standard remain in place, they actually raise the consumption of gasoline and could very well lead to fuel rationing as well as far higher diesel and gasoline costs.
We pay for this mess at least 4 ways:
1. We pay for the governmental subsidies to the alcohol producers and farmers.
2. We pay more for gasoline mixed with alcohol.
3. We pay for more gasoline as a result of poorer gas mileage.
4. We pay more for the food on our tables.